Problem: Evaluate $8-\dfrac {m}{n}+p^2$ when $m=8$, $n=2$, $p=7$.
Explanation: Let's substitute $ p = 7$, $ m= {8}$, and $ n={2}$ into the expression. $\phantom{=}8-\dfrac { {m}}{ n}+ p^2$ $=8-\dfrac { {8}}{ 2}+7^2$ $=8-4+49$ $=53$